Thomas j



(No Model.)

T. J. NICHOLSON,

- VENTILATING TOP FOR GHIMNEYS.

Patented Mar. 5, 1889.

WITNESSES. INVENTDRI N Panesv Phcio-Lll'iognphur. washingflumncllnrrnn STATns PATENT @rrice.

THOMAS J. NICHOLSON, OF LOFEYILLE, KENTUCKY.

VENTILATING TOP FOR CHIMNEYS.

SPECIFICATION forming part of Letters Patent No. 399,067, dated March 5, 1889.

Application filed November 28, 1887, Serial No. 256,802. (No model.)

' in both views.

M y invention relates to the class of stationary ventilating tops for chimneys, and is intended to increase or protect the draft of chimneys provided with it in windy weather without impeding it when the weather is calm.

In all other devices meant to be attached to chimney-heads for the purpose of as sisting or protecting the draft of the chimney that have come under my observation there is embraced a close hood or cover directly above the smoke-exit, which hood or cover is generally in the shape of a hollow inverted cone, but sometimes is a flat circular plate, or shaped like a round bowl, with the concavity downward. This cover is meant to shield the flue from downward blasts of wind; but its effects when the air is calm are inj urious for the followingreasons: The column of smoke rising from. the chimney strikes against the cover, and its movement is mementarily checked. As soon as it is thus checked or retarded, it begins to deposit soot more rapidly. This checking of the column of smoke also diminishes the draft. One of the principal objects of my invention is to provide a chimney-cowl in which the use of this cover over the smoke-exit, fouling the chimney, and obstructing the draft may be dispensed with, and protection against downward blasts of wind secured by substituting for that objectionable device the two flanged hollow conical frustums hereinafter described. [accomplish this by the following arrangement and construction of parts:

A pipe, 8, suitable to be inserted in a chimney-flue, and. which may be extended by joints, so as to raise the top to any height desired above the chimney-head, has aflixed to it at its upper orifice a horizontal flange projeeting outwardly for about three inches. On this flange and firmly attached to it is placed a device in the shape of a hollow conical frustum, 6, the lower base of which is of the same diameter as the flange and its upper base of a diameter about one inch less than the diameter of the flue-pipe 8. When this frustuni is of such aheight that its upper base has a diameter one inch less than the diameter of the lower base, its shape is changed from conical to cylindrical for about one inch, so as'to provide a vertical cylindrical flange around the upper base of the trust-um. Above the hollow frustuni 6, and surrounding its upper part, so as to leave a wind-space between them, is placed a similar flanged frustum, 5, with its walls oblique to the walls of the first frustum, so that the wind-space between them is narrowest at its lower base. Above the frustum 5, at a distance of about six inches, is placed another conical frustum, 1, having a horizontal flange, 3, about three inches wide, projecting outward from. its base. Supported within this, so as to leave a wind-space between them, is a similar but smaller frustum rising to about two-thirds of its height and projecting about an inch below it, having a similar but shallower flange at its lower base, or preferably a flange projecting obliquely downward instead of horizontally, having its lower base of the same diameter as the pipe 8, and its walls at such an angle with the walls of the outer frustu-m that the wind-channel between them is narrowest at the lower base of the outer one. The f rustum 5 is supported above 0 by braces, two of which, 7 7, are shown in Fig. 1. The frustum l is supported above 5 by braces i l l i, and the inner frustuni of the double top is supported by braces (not shown) riveted to the upper surface of the flange of E3 and the lower surface of the flange of 1.

The functions of the differentelements of my device will. be shown by a description. of its operation.

In calm weather the smoke rises vertically upward through the pipe 8 and the open frustum above it, issuing freely from the top of .1, thus avoiding the lessening of the draft and the deposit of soot, which are caused when the movement of the smoke is checked by the use of a cover over the'aperture. The smoke passing through the frustums 2 and 1 warms their walls, thus generating an increased draft to draw the smoke through the clear space left between 2 and 5. Upward blasts of wind increase the draft. Lateral gusts of wind will be deflected by the different frustums as follows: Part intercepted between (3 and 5 on the side next the wind will be directed upward by the vertical flange of 6; part striking on 5 will be similarly directed upward by its flange; part intercepted by the flange of 2 and carried upward though the wind-channel between it and 1, and part striking the upwardly-sloping walls of 1, will all increase the updraft, so that it will require a very strong horizontal wind to break the column. of smoke while passing through the clear space between 5 and the double top above. In case of such a wind the updraft through the wind-channel between 5 and 6 will prevent any eddying in the mouth of 5.

In case of downward gusts of wind directly from the zenith, which are rare, but the most troublesome, the operation of my ventilatortop will be as follows: That part of the clownblast striking the sloping outer surface of 1 and its flange 3 will be deflected forcibly outward before being bent downward, and that part intercepted between the frustums 2 and 1, increased in strength by being forced through the narrowing wind-space, will also be deflected outward by the flange of 2 before hein g bent downward, thus creating an outward and downward suction, affecting the contents of the open space between 5 and the double top above. The unintercepted part of the blast coming down vertically through 2 and widening as it descends through that frustum will meet in the open space the ascending column of smoke somewhat narrowed by pass ing through the frustum 6, and both will be drawn outward. by this suction. In case the central part of the vertical downblast is strong enough to force its way into the orifice 1 less top part consisting of a hollow conical frustum with a horizontal flange projecting outward from the rim of its lower base, surrounding a small similar frustum rising to about two-thirds of its height and projecting below it, havin a horizontal flange, the walls of the two frustums being inclined obliquely toward each other, the diameter of the lower base of the smaller being greater than the diameter of the flue-pipe below, and both being open at the top.

2. In a ventilator-top for chimneys, the 5 combination, with a flue-pipe, 8, having a horizontal flange projecting outwardly from the rim of its orifice, of a hollow conical frustum, 6, having a vertical cylindrical flange around its upper base, which is less in diameter than the pipe S, a similar frustum, 5, similarly flanged, having the diameter of its upper base the same as that of S and its walls inclined obliquely to those of 6, so as to have a wind-channel narrowing downward between them, and a capless top part raised over 5, so as to leave an open interval consisting of a hollow conical frustum, 1, having a horizontal flange, 3, surrounding a smaller flanged frustum, 2, having the diameter of its lower base greater than that of 8, all the frustums being open at the ends and braced together and arranged substantially as set forth, and for the purpose specified.

T. J. NICHOLSON.

\Vitnesses:

HARRY STUcKY, JNo. S. LoNo. 

